The present invention relates to control apparatus and method for an automatic transmission, capable of performing a shift-torque increase control for temporarily increasing torque of a drive source against pull-in torque, e.g., at a time of coast downshift caused by an accelerator release.
U.S. Pat. No. 7,503,873 (corresponding to Japanese Patent Application publication No. 2006-69267) discloses a previously proposed control apparatus for an automatic transmission. In this technique, a fuel cut recovery is started during the coast downshift conducting a fuel cut, by detecting a drop of turbine rotational speed which occurs when a high-speed-side engagement element (friction element) is released so as to cause a neutral state.
In this technique, by carrying out a fuel cut recovery control during the downshift, a pull-in amount of torque is reduced during a torque phase before a start of inertia phase so that a pull-in shock is suppressed.
The “torque phase” is one of phases which occur during a progress of shift, and is defined as a phase in which an input rotational speed of the transmission does not vary and only an output-shaft torque of the transmission varies. Moreover, the “inertia phase” is one of phases which occur during the progress of shift, and is defined as a phase in which the input rotational speed of the transmission varies mainly due to an inertia change of drive system.